//typeof

console.log(typeof 123);//number
console.log(typeof '123');//string
console.log(typeof true);//boolean
console.log(typeof undefined);//undefined
console.log(typeof null);//object
console.log(typeof {});//object
console.log(typeof []);//object
console.log(typeof function(){});//function
console.log(typeof Symbol());//symbol
console.log(typeof BigInt(123));//bigint
